The present invention relates to a joystick controller for electric switches, of the type which is used for controlling the operation of certain electronic games and the like. In particular, this invention relates to an analog joystick controller, i.e., a controller of the type which produces an output signal which varies continuously with the movement of the handle shaft.
In a typical analog joystick controller, the handle shaft is mechanically coupled to the wipers of two potentiometers, so that tilting movement of the handle along two perpendicular axes respectively varies the impedance of the two potentiometers. Prior analog joystick controllers have provided zero adjustment means for moving the resistance portion of each potentiometer with respect to its wiper to adjust the potentiometer to a zero impedance value corresponding with a predetermined home position of the handle, typically a centered position. These zero adjustment mechanisms have involved compound linkages between the potentiometer and a manual actuator, the linkage comprising plural parts resulting in a complex structure which is difficult to assemble and expensive to manufacture.
Prior analog joystick controllers have also provided means for selectively operating the controller in either one of two operating modes, viz., a positive positioning mode, wherein wherever the joystick handle is moved it maintains that position until it is manually moved again by the user, and a self-centering mode, wherein the joystick handle is biased to a center home position. The bias means are typically tension springs and the prior selection means is operated in such a way that when the positive positioning mode is selected, the springs are held in a maximum tension position. This places undue stress on the bias springs and results in their loss of elasticity and possible failure.